本文提出一种基于偏振旋转光反馈下的外光注入垂直腔表面发射激光器(VCSEL)产生高性能毫米波的方案,并利用描述外部扰动下VCSEL动态特性的自旋反转模型(SFM),对所产生的毫米波的特性进行了数值研究.研究结果表明:一个受到主VCSEL(M-VCSEL)光注入的副VCSEL(S-VCSEL)在一定条件下可以产生单周期(P1)振荡,即在光波上调制了一个微波信号.通过调节外光注入强度ξi以及S-VCSEL与M-VCSEL之间频率失谐△v,可以获得频率在30—60GHz范围内连续可调的毫米波信号.在外光注入VCSEL中引入偏振旋转光反馈,通过选取合适的反馈强度ξf以及反馈延迟时间Τ,产生的毫米波信号的线宽可以得到明显窄化.对于光注入S-VCSEL所产生的线宽为5.509 MHz的毫米波,在引入偏振旋转光反馈后,毫米波线宽可以降低到230.2 kHz.本文的研究对高速光载无线(RoF)系统中优质毫米波信号的获取具有一定的参考意义.
A scheme of optical generation of high-quality millimeter-wave based on the optically injected vertical-cavity- surface-emitting laser (VCSEL) subject to polarization-rotated optical feedback is proposed in this paper. Based on the spin-flip model (SFM), wich ex- ternal disturbances taken into account, the performances of the millimeter-wave generated by this scheme are numerically investigated. The results show that under suitable operation conditions, a slave VCSEL (S-VCSEL) injected by a master VCSEL (M-VCSEL) will operate in a period-one (P1) oscillation state and the output optical intensity of S-VCSEL looks like being modulated by a microwave signal. By adjusting the injection strength ξi and the frequency detuning Au between S-VCSEL and M-VCSEL, a millimeter-wave, whose frequency can be continuously adjusted in a large range from 30 GHz to 60 GHz, is obtained. After introducing polarization- rotated optical feedback, the linewidth of millimeter-wave can be obviously narrowed by adjusting the feedback strength ξi and the feedback delay time T. For a millimeter-wave with a linewidth of 5.509 MHz, generated by the optically injected VCSEL, its linewidth can be reduced to 230.2 kHz under optimum feedback parameters. The results obtained in this paper are helpful for acquiring highquality millimeter-wave used in high speed Radio-over-Fiber (RoF) system